Articulated pendulum steering system

ABSTRACT

Articulated pendulum steering for construction vehicles, in particular, for wheeled loaders which connects the front vehicle section ( 6 ) to the back vehicle section ( 7 ) in such a way that both the operator controlled steering motion and a pendulum motion between both vehicle sections ( 6, 7 ) occur. Basically, the articulated pendulum steering consists of a vertical bearing pin ( 2 ) and an almost horizontally arranged movable joint pin ( 8 ). On the vertical pin ( 2 ) a bearing ring ( 3′, 3″ ) sits both in the upper and in the lower area that is held in place by cup shaped supports ( 4′, 4″ ) which each are fitted onto one of two arms ( 5′, 5″ ) on the front vehicle section ( 6 ). Both arms ( 5′, 5″ ) extend into fork-like structural openings of the articulated pendulum joint ( 1 ). On the rearward front side of the movable joint pin ( 8 ) an extension pin ( 16 ) is fitted on which another bearing ring ( 9 ) sits. This bearing ring ( 9 ) is held in place by a bearing shell ( 10 ) that is fitted onto the cross beam ( 11 ) of the back vehicle section ( 7 ). Approximately in the center of the movable joint pin ( 8 ) a horizontal bearing pin ( 12 ) is fitted in lateral direction to the vehicle in the center of which another bearing pin ( 13 ) sits which is also held in place by a bearing shell ( 17 ) that is fitted onto the back vehicle section ( 7 ) of the vehicle. Bearing rings ( 3′, 3″, 9, 13 ) could be coated with, for example, Teflon. Bearing shells ( 4′, 4″, 10, 17 ) could also be coated with Teflon. Additionally, it is possible that the sliding surfaces of the components that pivot against each other are lubricated. The center of gravity of the back vehicle section ( 7 ) lies under the pendulum axle.

[0001] The present invention relates to an articulated pendulum steering for construction vehicles, in particular, for wheeled loaders. The articulated pendulum steering connects the front vehicle section to the back vehicle section in such a way that both the operator controlled steering motions and a pendulum motion between both vehicle sections occur. The steering motion causes a swivel movement of the front vehicle section or front frame of approximately +/−40° around the vertical steering axle of the articulated pendulum steering. The pendulum motion causes the front vehicle section or front frame to be pivoted a few degrees around an almost horizontal axle. The advantage of using articulated pendulum steering to fasten the front vehicle section to the back vehicle section is that the wheel axles of the construction vehicle can be easily fastened.

[0002] In order to perform the pendulum motion using simple articulated steering it is necessary to take other measures such as, for example, oscillation of the rear axle.

[0003] Construction vehicles, in particular wheeled loaders, are often employed in an environment having loose underfoot conditions. Therefore, it would be advantageous if these construction vehicles were designed for optimum maneuverability and compactness.

[0004] Conventional articulated pendulum steering basically consist of an articulated pendulum joint fitted with a vertical bearing pin and with a movable joint pin, the longitudinal axis of which forms the pendulum axle and which is almost horizontally arranged. Construction vehicles fitted with conventional articulated pendulum steering show the vertical bearing pin and the horizontal movable joint pin being held in cylindrical bushings that are fitted onto the front vehicle section or, as the case may be, the back vehicle section. The area of contact between the bearing pin or, as the case may be, the movable joint pin and the bushing must continuously be lubricated. This leads to increased maintenance costs during operation of the construction vehicle. Additionally, it must be taken into consideration that such construction vehicles often are leased and that, therefore, it cannot be guaranteed that the components are always sufficiently lubricated, which in turn also will lead to significant maintenance costs due to wear.

[0005] Therefore, it is an object of the present invention to provide an articulated pendulum steering which can be maintenance free and which facilitates designing the construction vehicle to be compact and maneuverable.

[0006] This object is achieved in accordance with the invention by holding the vertical bearing pin in two articulated joint bearings and by holding the movable joint pin in two pendulum joint bearings. The vertical bearing pin is thus held both in the upper and in the lower section by an articulated joint bearing and the movable joint pin is held both in the center and at the rear by a pendulum joint bearing. It is essential for the implementation of the present invention to note that by fitting one of the pendulum joint bearings on the front side of the movable joint pin and the other pendulum joint bearing in the center of the articulated pendulum joint the construction of a particularly compact construction vehicle is facilitated.

[0007] The joint bearings used in the articulated pendulum joint according to the invention consist of

[0008] a movable joint ring that sits on the respective bearing pin, the inner surface of said movable joint ring is flat and the outer surface of said movable joint ring is curved,

[0009] and the mating connector of the movable joint ring is a bearing shell that has a correspondingly curved opening to, at least partially, be able to receive the movable joint ring.

[0010] The bearing shells of both articulated joint bearings are fitted onto the front vehicle section of the construction vehicle and the bearing shells of both pendulum joint bearings are fitted on the back vehicle section.

[0011] The employment of joint bearings instead of the usual bearing pins minimizes the area of contact surface of the mechanical components that pivot against each other. Accordingly, it becomes relevant from a cost effective perspective to choose a high quality but low maintenance material for the coating or, as the case may be, for the mechanical components that are in contact with each other.

[0012] The drawings below merely represent one possible embodiment of the solution according to the invention. They show:

[0013]FIG. 1 shows a side view of a cross section of the articulated pendulum joint according to the invention,

[0014]FIG. 2 shows a plan view of a cross section through the articulated pendulum joint according to the invention,

[0015]FIG. 3 shows a construction vehicle fitted with the articulated pendulum joint according to the invention,

[0016]FIG. 4 shows a plan view of a construction vehicle and the maximum possible steering angle and

[0017]FIG. 5 shows a perspective view of the articulated pendulum joint.

[0018]FIG. 1 is a side view of a cross section of the articulated pendulum joint 1 according to the invention. Both in the upper and the lower sections of the vertical bearing pin 2 a bearing ring 3′ and 3″ sits that supports the articulated or, as the case may be, the steering axle. The mating connector, in other words, the bearing shells 4′ and 4″ for the bearing rings 3′ and 3″ are each fitted on an arm 5′ and 5″ on the front vehicle section 6 of the construction vehicle.

[0019] An extension pin 16 which is also fitted with a bearing pin 9 towards its end is arranged on the front side of the movable joint pin 8 centrally to the pendulum axle for the support of the pendulum axle. The mating connector, in other words, the bearing shell 10 is fitted onto a stabilizer bar 11 on the back section of the vehicle 7. It is clear from this view that both arms 5′ and 5″ extend into the fork-like structural openings of the articulated pendulum joint 1. Secondly, a horizontal bearing pin 12 for the support of the pendulum axle is fitted parallel to the cross axis of the construction vehicle approximately in the center of the articulated pendulum joint.

[0020] The horizontal bearing pin 12 is clearly visible in FIG. 2 which shows a plan view of a cross section through the articulated pendulum steering according to the invention. It is held in place by a second pendulum joint support approximately in the center of it. The bearing ring 13 that sits on the horizontal bearing pin 12 is circular and the inner surface of it lies flat against the bearing pin 12. The curved surface of the bearing ring 13 fits in a cup shaped opening 17 at the back part of the vehicle 7. The forward pointing end of the pendulum axle runs centrally along the longitudinal section through the bearing ring 13 and the rearwards pointing end runs centrally through the cross section of the bearing ring 9 which is not visible in this view since it is fitted in the stabilizer bar 11.

[0021] The panel 14, which is positioned separately from to the articulated pendulum joint 1, limits the pendulum motion as it reaches the position stop on same.

[0022]FIG. 3 shows a wheeled loader fitted with the articulated pendulum steering according to the invention. Both the precisely vertically aligned steering axle and the virtually horizontally aligned movable joint pin 8 are evident from the figure. In this embodiment the movable joint pin 8 is not precisely horizontal but rather is arranged in a slightly ascending position to allow the extension of the pendulum axle to run above the center of gravity of the back vehicle section 7 of the wheeled loader. This advantageous alternative pendulum axle tilting enables the pendulum axle to run upwards in the direction of the rear of the vehicle which means that when the lifter arm of, for example, a wheeled loader is impacted with such force that the back wheels are raised from the ground the back vehicle section 7 will not tip about the pendulum axle because the center of gravity lies under the pendulum axle.

[0023]FIG. 4 shows a plan view of the embodiment with a wheeled loader. The maximum possible articulation angle or, as the case may be, the maximum steering angle of plus or minus 40° from the base line that describes the angle when the vehicle is driven straight is indicated.

[0024]FIG. 5 shows a perspective view of the articulated pendulum joint 1 that clearly shows how the movable joint pin 8 is attached onto the back vehicle section 7. It is, on the one hand, the cross beam 11 on which the bearing shell 10 is fitted and, on the other hand, the protrusions of which only the one numbered 15 is visible that carry the horizontal bearing pin 12. The movable joint pin 8 is, at least partially, angular in the upper section. A panel 14 that function as front panel for the back vehicle section 7 is positioned separately from the movable joint pin 8 and is firmly attached to the back vehicle section 7 where it limits the pendulum motion.

[0025] In a best mode there is at least one Teflon coated bearing ring 3′, 3″, 9 or 13. In another best mode there is at least one Teflon coated bearing shell 4′, 4″, 10 or 17.

[0026] In an additional best mode at least some of the sliding surfaces of the components have been lubricated.

[0027]FIG. 1: Lenkachse: Steering axle

[0028] Pendelachse: Pendulum axle

[0029]FIG. 2: Lenkachse: Steering axle

[0030] Pendelachse: Pendulum axle

[0031]FIG. 3: Lenkachse: Steering axle

[0032]FIG. 4: Lenkachse: Steering axle

[0033] Lenkwinkel: Steering angle 

1. Articulated pendulum steering for construction vehicles, in particular, for wheeled loaders which connects the front vehicle section to the back vehicle section in such a way that both the operator controlled steering motions and a pendulum motion between both vehicle sections occur. Said articulated pendulum steering basically consists of a vertical bearing pin and an almost horizontally arranged movable joint pin characterized by the fact that partly movable joint supports are employed to support the vertical pin (2) and the movable joint pin (8).
 2. Articulated pendulum steering in accordance with claim 1, characterized by the fact that a bearing ring (3′ and 3″) sits on both the upper and the lower areas of the vertical steering pin (2).
 3. Articulated pendulum steering in accordance with claim 1 or 2, characterized by the fact that the bearing rings (3′ and 3″) that sit on the vertical pin (2) are supported by bearing shells (4′ and 4″) that are fitted on the front vehicle section (6).
 4. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that the bearing shells (4′ and 4″) each are fitted to an arm (5′ and 5″) on the front vehicle section (6) which extends into fork-like structural openings of the articulated pendulum joint (1).
 5. Articulated pendulum steering in accordance with one of the above claims characterized by the fact that an extension pin (16) is fitted on the rear front axle of the movable joint pin (8).
 6. Articulated pendulum steering in accordance with claim 5, characterized by the fact that on said extension pin (16) a bearing pin (9) is fitted.
 7. Articulated pendulum steering in accordance with claim 6, characterized by the fact that the bearing ring (9) is held in place by a bearing shell (10) that is fitted onto the back vehicle section (7).
 8. Articulated pendulum steering in accordance with claim 7, characterized by the fact that the bearing shell (10) is attached to a cross beam (11) on the back vehicle section (7).
 9. Articulated pendulum steering in accordance with one of the above claims characterized by the fact that approximately in the center of the articulated pendulum joint (1) a horizontal bearing pin (12) is fitted in lateral direction to the vehicle.
 10. Articulated pendulum steering in accordance with claim 9, characterized by the fact that a bearing ring (13) sits in the center of the horizontal bearing pin (12).
 11. Articulated pendulum steering in accordance with claim 10, characterized by the fact that the bearing shell (17) for the bearing ring (13) on the horizontal bearing pin (12) is fitted onto the on the back vehicle section (7).
 12. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that the pendulum axle is slightly elevated in rearwards direction.
 13. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that the center of gravity of the back vehicle section (7) lies under the extension line of the pendulum axle.
 14. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that at least one of the four bearing rings (3′, 3″, 9 or 13) is coated with Teflon on the inner surface or on the curved exterior surface.
 15. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that at least one of four bearing shells (4′, 4″, 10 or 17) is coated with Teflon on the curved surface or is made from said material.
 16. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that the vertical bearing pin (2) consists of two components.
 17. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that a steering motion of plus or minus 40° from the operating direction of the vehicle is possible.
 18. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that the pendulum motion between the front vehicle section (6) and the back vehicle section (7) is limited.
 19. Articulated pendulum steering in accordance with claim 18, characterized by the fact that the front panel of the back vehicle section functions as position stop during the pendulum motion.
 20. Articulated pendulum steering in accordance with one of the above claims, characterized by the fact that the sliding surfaces on the components that pivot against each other are lubricated. 